<html lang="zh">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>变量</title>
</head>
<body>
</body>
<script>
    var num1=070;//八进制,等于十进制的56
    var num2=0x1f;//十六进制,等于十进制的31
    console.log(num1,num2);
    //js保存的值不会无穷大 当数据超出时会转化成特殊的数据类型 lnfinity
    console.log(isFinite(21));//返回true
    console.log(isFinite("hello world"));//返回false
</script>
</html>